THE’Hurricane Milton hit the west coast of Florida at 2:30 a.m. (Italian time) on October 10, 2024, resulting in fatalities, destroyed buildings, 2 million homes without electricity and spawning at least 27 tornadoes. It was a hurricane that surprised climatologists and meteorologists by its extraordinary rapidity of developmentdue to several factors including the water temperatures in the Gulf of Mexico, its small size and the speed of the winds at altitude. All you need to know is one thing: on the day of Monday 7 October 2024shortly before passing off the Yucatán peninsula, in the space of just 7 hours passed by category 1 of the hurricane classification scale (the lowest), with sustained winds up to 150 km/hto a devastating one category 5 (the highest), with winds up to 260 km/h which then reached a maximum of 285 km/h.
To be clear, meteorologists define “quick” the intensification of a cyclone when the speed of sustained winds increases by at least 55 km/h in 24 hours: here instead we are talking about an increase of 110 km/h in 7 hours! Over the course of 24 hours (between October 6th and 7th) Milton’s winds increased by 153 km/h, almost triple!
This is an exceptionally fast intensification, to be precise third fastest never observed for a tropical cyclone in the Atlantic Ocean. This sudden jump in intensity led Milton to enter the top 10 of the most violent hurricanes recorded in the Atlantic and one of the most intense in the last 100 years. The reasons why Milton intensified so quickly are not entirely clear, but we do know what elements contributed to his strengthening.
Why Milton got so violent: Temperatures in the Gulf of Mexico
First, a hurricane’s “energy store” is thermal energy from ocean surface waters. In simple words, the warmer the waters, the more energy the hurricane can accumulateand consequently the more the hurricane gains power, in a self-sustaining mechanism. Milton, like the recent Hurricane Helene, formed in a Particularly warm Gulf of Mexicoas shown in this satellite image collected by NOAA which shows with a color scale the surface water temperatures recorded on October 7, the day of the very rapid intensification of the hurricane. As you can see, the temperatures in the area where Milton passed were around 30°Ca very high value for the month of October.
The size of Hurricane Milton
A final element to explain Milton’s rapid evolution is linked to his own relatively small size. You can understand this by looking at the image below, which shows the three cyclones present in the Atlantic in recent days: Milton, Leslie and Kirk. It is clearly noted that Milton is a relatively small hurricane in terms of size.
Smaller hurricanes tend to intensify more quickly: in general they increase or decrease in power more quickly. Its small size therefore probably helped it reach category 5 in almost record time.
The contribution of vertical wind shear: the role of winds at altitude
According to experts, another factor that may have contributed to Milton’s rapid intensification is a low difference between speed of the winds between the atmosphere at sea level and that at high altitude. It is the parameter which in technical jargon is known as vertical wind shear. This vertical gradient in wind speed actually helps a hurricane to grow in height, which in turn helps to strengthen it: the higher the temperature difference between the lower and upper levels of the hurricane, the more energy it can gain.
